MixedThe Wall Street Journal... ambitious and surreal ... Outside these few scenes and interviews, however, with their clashes of wealth and terror, The Great Successor falls flat. It is not a full-dress portrait of Kim Jong Un or a reported journey inside his ultra-secret regime. It reads like a chatty succession of newspaper articles—an amalgamation of interviews, photographs and state-media sources—that go around in circles, repeating themselves, jumping between times and places ... As a result, the book lacks the coherent storytelling and psychological insight that propel the best biographies. We learn that Mr. Kim has loved power since childhood, throwing tantrums and bossing around his cook. But we never know for sure what he thinks about economic reform, nuclear weapons or his summits with President Trump. The Supreme Leader is ever-present, yet frustratingly distant ... Ms. Fifield attempts to compensate by accumulating small facts ... With this dearth of first-hand sources, though, Ms. Fifield passes off conjecture as fact ... Ms. Fifield’s effort to write a thorough portrait is admirable under the circumstances. But as long as archives are closed and the regime is standing, it is too early for a biography of this mysterious and impenetrable leader. Ms. Fifield does still report colorful stories, like Dennis Rodman’s absurd and tragic visits.